chemical pt2

Question 1

what is the role of smell

Answer 1

compliment to taste- creates flavour
warning system- signals something is wrong
communication system for pheromones- fertility
important cue for memory

Question 2

microsmatic

Answer 2

less keen sense of smell

• not crucial to survival
  ex. humans have around 10 million olfactory

Question 3

macrosmatic

Answer 3

keen sense of smell 
-necessary for survival 
ex. rats, dogs, bees have 1 billion olfactory receptors
rats are 8-50x more sensitive
dogs are 300-10,000x more sensitive

Question 4

highest odor detection compound

Answer 4

t butyl mercaptan 0.3 parts per billion

Question 5

odor discrimination

Answer 5

ability to tell difference between odors

• participants chose which one is different from other 2
• humans can discriminate more than 1 trillian stimuli

Question 6

odor identification

Answer 6

name the substance being smelled

• people are not good at this (45% accuracy)
• with training can be improved

Question 7

olfactory quality

Answer 7

hard to organize and describe odors

• no olfactory space similar to color space
• similar molecular structures can yield different odors and different molecular structures can yield similar odors

Question 8

olfactory mucosa

Answer 8

roof of nasal cavity

- molecules reach it through nostrils or from oral cavity of mouth via pharynx

Question 9

olfactory receptor neurons (ORN)

Answer 9

transduce odorants into neural signals

• 400 types of receptors
• 10,000 neurons for each receptor type
• 4 million ORNS
• each 10,000 ORN for each type project onto 1 or 2 glomeruli

Question 10

ORN purpose

Answer 10

cilia of ORN contains odorant receptor proteins
- second messanger cascade causes Ca and Na to open and Cl to exit
ORN fires AP

Question 11

recogn ition profiles

Answer 11

odorants are coded by patterns of activation of olfactory receptors

• combinatorial codes for odor
• molecules with similar structure but diff smell have diff recognition profiles

Question 12

is there a chemotopic map

Answer 12

found different areas for different families of chemicals

• gradient from small to large molecules
• unsure why the placement is the way it is and if theres a larger organizational principle

Question 13

olfactory pathway

Answer 13

olfactory mucosa–> olfactory bulb–> piriform cortex (primary olfactory cortex) –> orbitofrontal cortex (secondary olfactory cortex) amygdala

Question 14

primary and secondary olfactory cortex

Answer 14

primary–> piriform cortex
- highly distributed activation for each odor
- odors may be represented as sparse distributed patterns across cortex
secondary –> orbitofrontal cortex

Question 15

oral capture

Answer 15

taste and smell experienced in mouth

Question 16

flavor

Answer 16

taste + smell

- molecules from food in mouth reach olfactory mucosa via retronasal route through pharynx

Question 17

critical areas for multimodal integration

Answer 17

orbital frontal cortex
insula
amygdala
- taste, smell, touch, vision, audition